The 23-year-old midfielder returned to United after having left for the Old Lady in 2012 for £1.5m, a nominal fee after his contract had expired.

"This is the right club for me to achieve everything I hope to in the game," Pogba said in his first interview back with the club.

"I am delighted to rejoin United. It has always been a club with a special place in my heart and I am really looking forward to working with Jose Mourinho."

'Heart of the club'

Manager Mourinho said the France international could be "the heart of the club for the next decade".

"Paul is one of the best players in the world and will be a key part of the United team I want to build here for the future. He is quick, strong, scores goals and reads the game better than many players much older than he is."

Mourinho, however, hinted that Pogba's arrival signalled the end of United's spending spree.

"Our fundamental market is 75 percent done," he said during United's pre-season tour of China.

"When we sign one midfield player that crucial work will be done."

Mourinho has been tasked with bringing back the glory days to the 20-time English champions after three lean years since Alex Ferguson's retirement.

His reign got off to a successful start on Sunday as Zlatan Ibrahimovic scored the winner in a 2-1 victory over Premier League champions Leicester City in the Community Shield.